The goal is to postpone circulatory collapse for at least 4 hrs (post hemorrhage) in severe hemorrhagic shock. This extension of the "Golden Hour" will be attempted in anesthetized pigs by administration of a novel, logistically very convenient treatment consisting in i.v. infusion of small doses (< 1.0ml/kg) of dodecafluoropentane emulsion (DDFPe), which at body temperature generates microbubbles that transport oxygen. A shock model which is fatal in pigs (controls) in 4 hrs will be treated at different points within this time interval. The ability of plasma expander administered thereafter to allow long-term (weeks) survival will be tested. A multitude of physiological and biochemical parameters will be monitored and organ histology studied. Markers of circulatory collapse will in particular be: subnormal tissue oxygen tensions in brain, liver, kidney and skeletal muscle, reductions in heart rate, deep body temperature and oxygen consumption, increasing lactacidemia and falling base excess and diuresis. Indicators of health during long-term survival include liver and kidney function tests. The project is expected to bring the DDFPe treatment to a state of scientific underpinning and applicability in the animal model which lays a solid foundation for pursuing FDA approval for human use.